Separate Souls by April Kelley

Three is better than two unless you’re the leader of an entire realm, the human is stubborn, and the dragon shifter doesn’t trust easily.
Sly’s one attempt at being a responsible adult goes sideways. For his next grand adventure, he plans on wallowing in self-pity. Having the flu makes that easy to achieve. He was getting rather good at it when two faeries from the otherworld landed on his failing farm and turned everything upside down. Two faeries on the farm are a lot, considering they aren’t supposed to exist, but another shows up to save the day. Turns out the beautiful woodland fae is his soulmate. Sly has some decisions to make, and quickly. Little does he know, but he has a broken dragon shifter mate who needs him, not just a woodland fae king.